1 Flashcards
What is the relationship between the speed, frequency and wavelength of a
waveform?
v=cλ (where v is frequency, c is the speed of light)
What are the properties of a photon
They have zero mass
In free space they move at the speed of light
They are discrete packages of energy, which is related to their wavelength (shorter wavelengths have more energy)
They can be absorbed (destroyed) and created (emitted)
They can have particle like interactions (i.e. collisions) with electrons and other atomic particles.
In the electromagnetic spectrum, approximately what range of wavelengths corresponds to each of these spectral colours? • Red • Green • Violet • Orange • Blue • Yellow
Red - 647-760nm Green - 491-575nm Violet - 381-424nm Orange - 585-647nm Blue - 424-491nm Yellow - 575-585nm
What are the relationships between the frequency, wavelength and energy
of a photon of light?
The greater the energy, the larger the frequency and the shorter the wavelength.
Define “transmitted light”
The movement of electromagnetic waves (whether visible light, radio waves, ultraviolet, etc.) through a medium.
Define “scattered light”
The movement of electromagnetic waves (whether visible light, radio waves, ultraviolet, etc.) through an imperfect medium, causing it to be deflected of its straight path and into many directions.
Define “absorbed light”
The process in which electromagnetic waves (whether visible light, radio waves, ultraviolet, etc.) is absorbed via a medium and converted into internal energy.
Define “fluorescent light”
The process in which UV light triggers a process in which visible light is emitted
Name each section of a spectrophotometer
Light source
Monochromator
Sample solution
Display meter
Complete the definitions as simple formulae:
% Transmittance =
Absorbance =
% Transmittance =%T = (Transmitted light (after) / Incident light (before)) × 100
Absorbance = log(Incident light (before)/Transmitted light (after))
What the following symbols represent? And what are their units A = L = c = Ɛ =
A = Absorbance (N/A) L = path length (cm) c = concentration (M) Ɛ = Extinction coefficient (M^-1cm^-1)
Explain the steps of purifying a protein from a tissue
- Extraction (Homogenization)
- Cell lysis (Due to extraction)
- Clarification (Centrifugation)
- Chromatographic fractionation
- Assay
- Purification (electrophoresis)
What does SDS polyacrylamide gel electrophoresis separate proteins based on?
Molecular weight (size)
What does non-denaturing polyacrylamide gel electrophoresis separate proteins based on?
Molecular weight (size), conformation (shape), charge
What does size exclusion chromatography separate proteins based on?
Molecular weight (size) and conformation (shape)
